Floc deformation and expulsion of interstitial fluid

The expulsion of interstitial fluid from flocs figures prominently in a wid e variety of solid-liquid separation processes. particularly wastewater tre atment and mineral processing. However, our understanding of flee structure , and particularly of how flocs respond to applied stress, is inadequate fo r some of the tasks at hand. An experimental technique has been developed i n which the vertical compression of individual clay-polymer flocs in a cyli nder-piston apparatus can be observed with macrovideography. The dynamics o f the compression process have been modeled and the results compared with e xperiment; the technique has shown an ability to differentiate between floc structures formed with different polymer dosing regimens. A model of the d rainage process for interstitial passageways indicates that modest-sized vo ids drain fairly rapidly relative to the time required for flee compression . This suggests that expulsion of fluid from passageways during compressive floc deformation generally occurs sequentially rather than simultaneously.